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VALVEBY GROUP:
1) NURUL NABILLATUL MUNIFA BT R.AZMI
2) NURUL SHAKIRA BT JOHARI
3) NURULFARAHANA BT HARUN
4) PUTRI NOOR NATASHA BT CHE YEO MEGAT
5) SHARIFAH SABIRAH BT SYED HAMZAH
CHECK VALVE
• Figure:
DESCRIPTION :
• Check valve (non-return valve) also known as one-way valve, reflux valve and back pressure valve.
• Are installed in pipeline systems to allow flow in one direction only.
• Pipeline used to prevent reflux of a fluid valve.
• Check valve are found everywhere, including in home.
• Check valve are used with a variety of media such as liquid, air, other gases, steam, condensate and in some cases liquids with fines or slurries.
FUNCTION:
• Prevent media backflow.
• Prevent pump.
• Prevent drive motor reverse.
• Discharge the container medium.
• Rise the pressure to exceed the system pressure auxiliary supply.
APPLICATIONS:
• Pump
Check valve often used with some type of pumps.
The feed pumps or injectors which supply water to steam boilers are fitted with check valves to prevent back-flow.
• Industrial processes
Check valves are used in many fluid systems such as those in chemical and power plants, and in many other industrial processes.
For example, if a fuel and an oxidizer are to be mixed, then check valves will normally be used on both the fuel and oxidizer sources to ensure that the original gas cylinders remain pure.
• Domestic Use
Check valves used in domestic heating systems to prevent vertical convection, especially in combination with solar thermal installations, also are called gravity brake.
Hydraulic jacks use ball check valves to build pressure on the lifting side of the jack.
TYPE :
• Swing Check Valve
• Lift Check valve
• Ball Check valve
• Diaphragm Check valve
• Stop Check valve
• Line Check valve
• Duckbill Check valve
• Multiple Check valve
• Dual Disc Check valve
• Titling Check valve
VIDEO:
Check Valve.avi.flv
DIAPHRAGM VALVE
• Figure:
DESCRIPTION :
• Transmits force to open, close or control a valve.
• Get their name from a flexible disc which comes into contact with a seat at the top of the valve body to form a seal.
• Diaphragm is a control device that utilizes a flexible membrane to close or shut, an opening.
• Consists of a valve body with two or more parts, a diaphragm and a “weir or saddle” or seat upon which the diaphragm closes the valve.
• The valve is constructed from either plastic or metal.
• Pressure increase or decrease on either side of the diaphragm cause the valve to move its position.
FUNCTION:
• Usually used at the home or for industrial factories.
• Used in industries like food processing, pharmaceutical manufacturing, mining and pollution control.
• Used on shut-off and throttling service for liquids, slurries and vacuum or gas.
• Should be used for processes where the absence of dead space inside the valve.
• Use to isolate or block flow.
APPLICATION:
• The diaphragm valve has an extended use for applications at low pressure and slurry fluid where most other kinds of valves corrode or become obstructed.
• Use the diaphragm to separate the flow from the closer element.
• Excellent for controlling the flow of fluids containing suspended solids and offer the flexibility of being installed in any position.
TYPE:
• Weir
Often used in pipes.
Can be used for either off or on and throttling services.
• Straight-through flow
Only used for on or off service.
Can be found at the bottom of tanks.
VIDEO:
Diaphragm Valve.mp4
REFERENCES:
• http://www.wisegeek.com/what-is-a-diapwhragm-valve.html
• http://www.rpi.edu/dept/chem-eng/Biotech-Environ/valves/diaphragm.html
• http://www.valvias.com/type-diaphragm-valve.php
SOLENOID VALVE
DESCRIPTION:
• An electrically operated valve where an electromagnet is used as actuator to change the valve state.
• Have two type: a)two-way solenoid valve
b)three-way solenoid valve
• In two-way solenoid valve, the valve is open when the solenoid coil is energized.
• The energized solenoid coil acts as an electromagnet which pulls the plunger and the valve disc upwards. The valve is closed when the coil is de-energized.
• In a three-way solenoid valve, energizing the solenoid coil cause the valve to open from port1 to port2 while de-energizing the coil causes the valve to open from port2 to port3.
• The closing action of the valve is achieved by the weight of plunger, valve stem and disc. Once the disc comes close to its seat, flow(from left hand side)will snap the valve tightly shut.
FUNCTION:
• Used only in an ON/OFF manner.
• Used in conjunction with a pneumatically actuated diaphragm control valve to obtain ON/OFF valve operation by an electrically applied signal.
VIDEO:
Solenoid Valve Working.FLV
REFERENCES:
• Lecture note(Valve In Industry Part2)
• Internet:http://youtu.be/cqvE3n7JXnU
BUTTERFLY VALVE
• Figure:
DESCRIPTION:
A butterfly valve consists of a circular disc with its pivot axis at right angles to the direction material is flowing. The valve is made up of a body, seat, disc, stem, and actuator. Each component part is available in a variety of materials called “trim features.” Properly combining trim features to address material handled and environment is important in selecting the correct model valve for its intended service.
Body: A butterfly valve body can be made of cast iron, ductile iron, aluminium, carbon steel, stainless steel and exotic metals.
Butterfly valves are available in wafer and lug style. Wafer style valves are installed “sandwiched” between pipe flanges. This style of valve is easier to replace or install. However, replacing a wafer valve requires the conveying line to be drained. Once the valve is removed, there is nothing to seal material either upstream or downstream from the removal point.
Lug style valves contain tapped holes that allow them to be bolted directly to a mating flange. In the closed position, the valve independently seals material to the upstream and downstream side. Because of this independent sealing, lug valves may be used to isolate downstream equipment that may require replacement or maintenance.
Seat:
Resilient seated valves are the most commonly used types. The interior of the valve body is lined with an elastomeric seat. Seats may be made of EPDM, Buna, viton, Teflon, natural rubber, carbox, chlorbutyl, white Buna, or white neoprene as well as other materials. Choice of seat material depends on temperatures, pressures and material handled.
The seats of some inexpensive butterfly valves are typically moulded into the body and cannot be repaired or replaced. Precision butterfly valves typically contain removable seats that are repairable or replaceable.
Disc:
The valve disc (controlled by the actuator) regulates the flow of material within the conveying line. Disc materials are available to meet a variety of application demands: stainless steel, aluminium/bronze, ductile iron, ductile/epoxy coated, ductile/nickel plated, ductile/nylon II coated as well as others. As the disc is directly in the material flow stream, care must be taken in specifying the proper material of construction and disc shape. Some discs are designed to allow increased flow patterns through the piping.
Stem:
The stem passes through the centre of the valve, attaches to the actuator, and positions the disc for material flow control and shut off. Depending on the application and valve size, stems may be one or two-piece construction. Typical materials of construction include carbon steel and different grades of stainless steel.
Actuator:
A variety of actuators are available for butterfly valves: manual handle, gear, pneumatic, electric and electro-hydraulic. Also, actuators that may be enclosed in special housings and buried are available for certain underground applications.
FUNCTION:
• A Butterfly Valve is used to control the flow of material through a circular pipe or tube. Typically the material is air, gas, steam, or liquid. Certain dry materials may also be handled through a butterfly valve.
APPLICATION:
As stated earlier, Butterfly Valves are generally specified for most air, gas, steam, and liquid applications. They offer an excellent, economic ally priced, positive shut-off valve for handling materials (e.g. gases and liquids) that are easily displaced by the valve disc as it closes.
When handling this type of material, butterfly valves provide a reliable, bubble-tight, bi-directional shut off. Care must be taken when applying a butterfly valve in semi-abrasive or abrasive dry material applications.
• this includes slurry applications that contain suspended particles because:
1) A valve disc closing on dry bulk material will create premature wear to the rubber seat.
2) The obstructed orifice created by the disc may cause bridging of material on the inlet side of the valve.
3) A disc opening or closing on a standing column of dry material may cause the material to jam / pack.
4) Particles of dry material or suspended particles in slurries may become trapped between the disc and seat, causing conveying line inefficiencies.
VIDEO:
butterfly valve.FLV
REFERENCES:
• http://www.bulk-online.com/Co/34338.htm
• http://www.valworx.com
PRESSURE RELIEF VALVE
• Figure:
FUNCTION:
• The function of a relief valve is to set the maximum pressure in a hydraulic system.
APPLICATION:
• Direct acting pressure/vacuum relief valves (also known as breather valves, conservation vents, or safety vents) are special types of relief valves which are specifically designed for tank protection.
• The range includes pressure only, vacuum only and combined pressure/vacuum valves, all available with flanged outlets or vented to atmosphere.
• Pressure / vacuum relief valves are used extensively on bulk storage tanks, including fixed roof tanks with floating covers, to minimise evaporation loss.
• The valves prevent the build up of excessive pressure or vacuum which can unbalance the system or damage the storage vessel.
• Pressure and vacuum protection levels are controlled with weighted pallets or springs and can be combined to provide the required pressure/vacuum settings.
• It is common to combine pallet and spring systems in one unit i.e. pressure settings require a spring section, whilst the vacuum settings use the pallet method.
TYPES:
• Pressure & Vacuum Relief to Atmosphere
• Pressure & Vacuum Relief to Atmosphere(Spring Loaded)
• Pressure Relief to Atmosphere
• Vacuum Relief from Atmosphere
• Pressure Relief to Closed Line
• Pressure Relief to Atmosphere Vacuum Relief from Closed Line
• Pressure Relief to Closed LineVacuum Relief from Closed Line
• Vacuum Relief from Closed Line
PRV- Pressure Relief Valve.flv
REFERENCES:
• http://www.elmactechnologies.com/products/pressure_vacuum_relief_valves.html?gclid=CLOPtf6L7LkCFbF34godtVAAwA
• http://valveproducts.net/relief-valve/operation-principle-of-relief-valve
NEEDLE VALVE
DESCRIPTION:
• It is called needle valve due to the shape of the closure member.
• Needle valve suitable for regulating flow.
• It is possible to easily adjust the flow rate to any specific amount desired.
• Designed with a metal needle.
• Valves are available that have metal - metal, plastic – plastic, or plastic- metal needles and seats.
FUNCTION:• Needle valves are widely used to accurate
regulate the flow of liquids and gases at low flow rates.
• Needle valves are used to control flow into delicate gauges.
• Needle valves are also used in situations where the flow must be gradually brought to a halt and at other points where precise adjustments of flow are necessary or where a small flow rate is desired.
• A needle valve is also sometimes used in equipment that controls the temperature of water within a specific system.
APPLICATION:
• the valve makes it possible to control the flow of water through the heater, a factor that can also aid in minimizing the amount of energy needed to maintain an equitable supply of hot water.
• At the plant level, valves of this type are often used to regulate the flow into the system used to deliver the product to various points of destination.
• For engines in which carburettors are commonly included, a needle valve is often the device that helps to regulate the flow of fuel into the device.
• A lack of sufficient fuel flowing into the carburettor will result in additional wear and stress on the engine over time, a factor that may lead to costly repairs.
• Needle valves are used in almost every industry in an incredibly wide range of applications - anywhere control or metering of steam, air, gas, oil, water or other non-viscous liquids is required.
TYPES:
• Butt Weld type • Integral Bonnet type
• Panel Mounted type
• Gauge Root Type
• Anguler type
ADVANTAGES:
• One common use of both stainless steel and brass needle valves is with utility meters where there is a need to measure precisely the amount of power, water or natural gas that a customer has consumed during a given billing period.
• At the plant level, valves of this type are often used to regulate the flow into the system used to deliver the product to various points of destination.
• By controlling the needle valve rate, stress on the delivery system is kept to a minimum, which in turn helps to enhance the safety of personnel who work at various points along that system.
DISADVANTAGES:
• Unlike other types of valves, there is no way to visually observe the position of the screw or the handle used to control the positioning of the screw and determine if the valve is open or closed.
• For this reason, other devices are often included in the equipment design that makes it possible to monitor the flow and use the valve to adjust that flow accordingly.
• These variations are usually designed with specific applications in mind, especially situations where corrosion, high or low temperatures or extensive wear are possible.
• In such cases, it is best to consult with the manufacturer to find which type of valve is best for the application at hand.
PLUG VALVE
DESCRIPTION:
• Plug valves are also known as ‘cock valves’.
• The plug also contains a port to allow the fluid flow as indicated in the figure. This port can be rectangular or round in shape.
• The rotation of the plug and hence the port, can be used to control the opening to allow the fluid flow.
• Plug valves are either cylindrical or conically tapered.
• The lubricated plug valve is of the "block" or complete shut-off type .
• Three basic parts comprise the lubricated plug valve: body, cover and plug.
FUNCTION:
• Plug valves are used in a wide array of equipment. They are usually found in natural gas lines as a device to control gas flow within the pipes, as well as laboratory glassware stopcocks in used in creating glass products and items.
• Plug valves are also used in vacuum devices, as part of the controls in removing pressure from a given amount of space.
APPLICATION:
• Air, gaseous, and vapour services
• Natural gas piping systems
• Oil piping systems
• Vacuum to high-pressure applications
TYPES:
ADVANTAGES:
• Plug valves have very simple design and fewer parts. Plug valves are easy to clean and can be cleaned without having to remove the body from piping system. Plug valves provide reliable leak tight service. Plug valves can be quickly opened or closed and they offer low resistance to the flow.
• Plug valve can minimal resistance to flow. The isolation of the downstream system from the upstream system by use of and isolation /stop valve is a critically important function..The prime requirements of this valve are tight shut off when closed and minimum restriction to flow when open.
• Plug valve also smaller in size than most other valves.
DISADVANTAGES:
• Due to large amount of friction to rotate the plug, greater force is required to operate the plug valves. For larger valves actuators may be needed. Usually plug valves cost more than ball valves, which have similar design.
• Reduced port, due to tapered plug. The plug and body tapered bores are matched together to form a relatively wide seat area. The plug bore is normally reduced but full port is available for slurry applications with high solid content where these valves are particularly more suitable than other types. Full port valves are considerably more expensive than reduced port and normally not used in hydrocarbon applications.
VIDEO:
Plug Valve.flv
REFERENCES:
• http://water.me.vccs.edu/courses/CIV240/plug_valves.htm
• http://www.flowserve.com/files/Files/Literature/ProductLiterature/FlowControl/Nordstrom/NVENBR1004.pdf
• http://www.youtube.com/watch?v=b9UjNErhlto
